Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 4,614,602	$ 10,843,055
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	45,919	228,135
Stock-based compensation expense	662,770	260,466
Deferred tax expense (benefit)	(176,802)	159,459
Non-cash lease expense	38,263
(Accretion) amortization of bond (discount) premium	370,193	(77,499)
Changes in operating assets and liabilities:
Accounts receivable	7,369,321	(210,949)
Income tax payable	1,318,067	173,690
Prepaid expenses and other current assets	(477,091)	(365,423)
Patent costs		(92,582)
Accounts payable, accrued expenses and lease obligation	1,060,916	(1,087,775)
Net cash provided by operating activities	14,826,158	9,830,577
Cash flows from investing activities:
Purchases of property and equipment	(69,470)
Maturities of marketable investments	60,592,693	42,451,229
Purchases of marketable investments	(63,126,006)	(53,104,080)
Net cash used in investing activities	(2,602,783)	(10,652,851)
Cash flows from financing activities:
Proceeds from stock option exercises	61,725	1,736,946
Payments for repurchase of common stock	(412,761)	(118,566)
Net cash (used in) provided by financing activities	(351,036)	1,618,380
Increase in cash and cash equivalents	11,872,339	796,106
Cash and cash equivalents at beginning of year	4,999,183	13,176,452
Cash and cash equivalents at end of period	16,871,522	13,972,558
Cash paid during the year for:
Taxes	$ 124,256	$ 1,826,362